A hard film is widely applied to surfaces of predetermined members of tool base materials such as high-speed tool steel and cemented carbide. Heat resistance (oxidation resistance at high temperature) of film is extremely important for high-speed machining of high-hardness work material, for example, and has considerable effect on tool life. For example, TiAlN-based and AlCrN-based films are conventionally known as such a hard film excellent in heat resistance (see, e.g., Patent Documents 1 to 5).